Re: [RFC PATCH v1 00/13] exec: add spawn templates for repeated executable startup

[Andy Lutomirski]

On Thu, May 28, 2026 at 2:55 AM Li Chen <me@linux.beauty> wrote:
>

>
> The template pins the executable and denies writes to that file while the
> template fd is alive,

Please don't.  *Maybe* detect when it gets modified and clear your cache.

Or develop a generic way to open a new fd that's an immutable view
into an existing file such that the fd retains its contents even if
the file changes.  (Think a reflink that's not persistent and has no
name -- you'll need some way to avoid resource exhaustion.)

>
> Workload     Calls  subprocess  spawn_template  time_s       Delta
> (workers)    calls  calls/s     calls/s         seconds
> 1x16         6144      411.04          420.32   14.95/14.62  +2.26%
> 2x8          6144      666.78          690.08    9.21/8.90   +3.49%
> 4x4          6144      955.61         1003.25    6.43/6.12   +4.99%
> 8x2          6144     1048.25         1069.18    5.86/5.75   +2.00%

This is a lot of complexity in the kernel for a teeny tiny gain.

I'm with Christian -- a better spawn API would be great (and much
faster than fork/vfork + exec), but that's a different patch.